Use when a task involves diagnosing a browser page with Chrome DevTools evidence from console, network, performance, or rendering panels to identify the intended outcome, relevant inputs, platform or version, sensitive data, and permission boundary before acting. Use current primary documentation for version-sensitive behavior, produce a reviewable artifact, and verify it against stated criteria. Trigger for planning, implementation, evaluation, or troubleshooting in this focused domain; do not install or run third-party commands without authorization.